Field of the Invention
The present invention relates to a piezoelectric material, and in particular, relates to a lead-free piezoelectric material, which does not contain lead. The present invention also relates to a piezoelectric element, a multilayered piezoelectric element, a liquid discharge head, a liquid discharge apparatus, an ultrasonic motor, an optical device, an oscillatory device, a dust removing device, an imaging apparatus, and an electronic device that use the piezoelectric material, and a method for manufacturing the piezoelectric element.
Description of the Related Art
Generally, a piezoelectric material is an ABO3-type perovskite metal oxide such as lead zirconium titanate (hereinafter referred to as “PZT”). PZT, however, contains lead as an A-site element, and therefore, the environmental impact of PZT is regarded as a problem. Thus, there is a need for a piezoelectric material using a perovskite metal oxide that does not contain lead.
As a piezoelectric material using a perovskite metal oxide that does not contain lead, barium titanate is known. Further, to improve the properties of the piezoelectric material, a material is developed based on the composition of barium titanate.
Japanese Patent Application Laid-Open No. 11-060334 discusses a material of which the piezoelectric properties (the piezoelectric constant) are improved by replacing a part of the B site of barium titanate with Zr to raise a phase transition temperature Tto to the room temperature range, and using a local maximum in the dielectric constant due to a phase transition.
To drive a high-power actuator, however, if room temperature is set to 25° C. and the room temperature range is set to, for example, 20° C. to 30° C., the piezoelectric properties of the piezoelectric material discussed in Japanese Patent Application Laid-Open No. 11-060334 are not sufficient within the room temperature range. Generally, the piezoelectric properties (the piezoelectric constant) increase near the phase transition temperature. In the case of the piezoelectric material discussed in Japanese Patent Application Laid-Open No. 11-060334, even if the amount of contained Zr is adjusted to shift the phase transition temperature of the piezoelectric material to near room temperature, the piezoelectric properties are still insufficient.